I just claimed mine and hid my phone number 
This feature is available in the 7.0.0 client. It may take a few weeks to roll out to all users via the app store, so you may not see it yet. Although you can guarantee having access today if you join their beta program.
Also: Confirmed that when you add a username and hide your phone number, your phone number is hidden from pre-7.0.0 clients:
(screenshot from someone else’s 6.47 client with no phone number visible on my profile)
Nice, but still seems that they require a phone number, right?
yes
It still that this is a nice step in the right direction. Thanks for sharing.
Just got the notification as well. Any idea when will rollout happen on forks like Molly?
Didn’t expect them to release now. As posts in signal community suggested it would require lot more time.
Nevertheless glad they finally brought this into reality on main server.
Hope signal is more widely adopted now.
Another reason to convince your friends to join signal !!
Really great from Signal! Of course, I would stay in the stable version of the app, as I want my setup to be the most stable possible. I’m excited about that 
If anyone wants to help test something, someone who isn’t on 7.0.0 should try messaging me with this link:
I’m curious whether username links work with 6.47.1 clients.
Edit: It does
So between this and that on older clients, people who are on 7.0.0 today should have phone number privacy from all Signal users even if the other end hasn’t upgraded to 7.0.0 yet.
A Signal username isn’t the profile name that’s displayed in chats, and isn’t visible to the people you chat with on Signal. A username is simply a way to initiate contact on Signal without having to share your phone number
If we interpret this correctly, it means a user can change their usernames after sharing it with few people. And these people won’t be informed about your new username.
So kinda protects you from some spam if someone whom you originally added tries to share your username ,with people you didn’t intend to.
I don’t see any update for the app on iOS?
I am not an iOS user but I think you need to join TestFlight Programme to obtain beta builds in iOS.
However for Android, beta builds can be obtained using Aurora Store if you have the build number, in this case, 139402.
Ah, yeah. I missed that is for beta, not for stable release. I am sure TestFlight is already capped.
Yes. It makes sense to minimize fraud/spam and for identity authentication. It has no real effect on privacy. For those who want anonymity, there are other messengers that are good for that (i.e. Session, SimpleX or even Matrix to an extent).
I’m a little confused about the username changing. You can change any time you want, so you can basically give out a username to someone and then change it after if you no longer want to be found by them. But let’s say someone else takes up your previous username, and you have someone or a group of people who still think they can find you under that username. Isn’t that a security issue that opens up possibilities for impersonation? Am I missing something?
I don’t believe previous usernames can be reclaimed by anyone. (see below)
Not only the privacy concern. Signal still a centralized platform, right?
It is. Technically, you could deploy your own private server, as it’s open source, and build the clients pointing to your server, and you could have total control, but you wouldn’t be able to communicate with anyone in the Signal network. So technically speaking it could be considered decentralised, but unfederated. But yes, the main Signal network where everyone is is centralised.
Just out of curiosity. What’s your concern with Signal being centralised? The server is only routing encrypted data and it has countermeasures for being able to connect to the service even if it’s being blocked by your country or ISP.
From the Signal support center, usernames do appear to be reclaimable:
Transfer username
You cannot transfer your username to another person or hold it for someone else to claim. Once you change your username, anyone can claim it soon.
This is… interesting. I guess this will never a be a problem as long as nobody you are no longer in contact with, tries to reach you via username you no longer operate.